Early factors in successful anti-HIV treatment.

Rapid suppression of plasma HIV RNA and sustained increase in CD4 cell count following highly active antiretroviral therapy (HAART) regimens can be prognostic indicators of long-term virologic treatment success. Routine measurement of plasma HIV RNA levels (viral load or VL) at four and eight or 12 weeks is recommended after initiating treatment because favorable changes are predictive of durable success at six months and longer. Early favorable response of VL, as soon as six days after HAART initiation, can signify that the patient is initially adherent to treatment, which is necessary in the long term for a successful regimen. Early favorable response is also an indicator of adequate pharmacokinetic profile and potent antiviral activity of the drug regimen. It also can indicate that the predominant HIV strain infecting the patient is sensitive to the treatment regimen. These factors of adherence, drug levels, potency, and susceptibility favor a long-term durable response. Evaluation of early treatment responses may create the opportunity to promptly change the HAART regimen in the event of an anticipated long-term failure, delaying or preventing the evolution of drug resistance, and improving the effectiveness of treatment overall.